Method and apparatus for permanent hair waving



March 25, 1941. J A MAXZE 2,235,895

METHOD AND APPARATUS FOR PERMANENT HAIR WAVING Filed April 2, 1938 2 Sheets-Sheet 1 I l i 5 -59 I l l I I I l l I 5 i I g 1 110 f l I 15 1 L March 25, 1941. MAIZE 2,235.895

METHOD AND APPARATUS FOR PERMANENT HAIR WAVING Filed April 2, 1938. 2 Sheets-Sheet 2 Wmpmmgmmmm Y 0 5mm 12/ 7 \x 69 t HZ Patented Mar. 25, 1941 it 1 U azaasasfl. a, qanz'rnon ANnnPrARA'ros'joaramuananr laines AlbertjMaiz e, Salt Lake City, Utah,assignor to llarry B. Stowe, SaltLake City, Utah, as l l trustee i lappiication'aprnz,lssa serialNonsense l llj Claims. (omit-44) This invention relates tothe art of permanent f hair waving, and has as a broad object to make it possible to accurately determine the optimum heating or steaming time without relying upon theexercise of skill by the operator.

Another object, is to indicate during the actual steaming of thehair the difierentstages ofthe cycle, of changes through which the'hair passes lntdl gthe process. i

,,Anotherobject is to provide a simple and reliable rnethodv and-apparatus for indicating changes in the electrical resistance of hair while the hair. is,in the ,process of being waved, Still, another object isitoj provide a simple'ap- ,pai atuslior, indicating when a predetermined 3 percentage change has. occurred in an electric current irrespective of the: absolute value ofthe current. i l a .The process of permanent waving of hair as it is generally :andalmosta universally practiced, consists in first, treating; the hair with a suitable solutiomsuch as ammonia, for example;= then winding or twisting thehair into the desiredconfiguration, and while still forcibly retained in that ccniiguration, applying heat to it for a period" of time, nder the influenceofthe solutionjand the heat, the hair. first becomes soft and plastic and assumes or acquirestthe twist or curl impartedto it. fIhenas the heating con tinues, .the hair recovers its strength and elast c y andif the heat is stopped acme proper time the hair is restored substantially to its orig inalphysical condition except thatait has the desired curl or wave permanently set in it.

It is important, to obtain agoods permanent wave, that the heating be stopped at just the right time. a If the time is too short, the wave is not as tight and permanent as it should be; it

the time is too long thebair may be injuredso that it becomes frizzy andsplitsbadly, particularly after a. few shampoos. Also, tooalong a heating period may actually be; productive of a weaker wave than the optimum time because the cycle of changesrecited sometimes repeats itself, under; which, condition the heating may be stopped while the hair isjin a, relatively plastic state. r i

Although it hasv previously been known, that the hair went through a definite cycle oi. changes and that it was important to stop the heating at just the right step in thecyclato the best of-my knowledge it has not previouslybeen known how the changestaking place in the hair could be determined and followedduring the heating period'. As a result, since difierent types and being wound with the hair;

grades offhair require different heating times,

careful operatorshave always made several test curls with different timingQp rior. to giving a l permanent wave. However, it is impracticable to make very many tests, and the time, as de- 5 cided by such tests, is usually only a. veryrough bestresults. i a i i In accordance with thetpresent invention, I have discoveredthat during the heating stagefof a permanent waving operation, the changes in the physical characteristics, i. e. strength and elasticity, areaccompanied by changes inthe. electrical resistance and that by determining and indicating the changes in resistance of the hair during the heating operation, the time when the heating should be discontinued can be easily and approximation of the optimum time to obtain the accurately ascertained.

More specifically, I have discovered that at the startingof the heating period, the resistance of the hair is high but that it drops as the; heating continues and the hair becomes plastic, but then increasesas the hair recovers its,,strength and elasticity, returning almost, but not quite, to its I have further discovered that the optimum time of heating for any jpar ticular hair can be determined sufliciently definitely for practicalpurposes from the electrical resistance cycle of that hair, "and that definitely uniform waving results can be ;obtained inall cases by terminating the heatinghperiod when the electrical resistance of the hairha s risenlto a value bearing; a definite ratio to the minimum value it reached during theearlier stages of the heating period (the most plastic). n

For the purposeflot explaining the invention, a} preferred apparatus and procedure will now .be described in detail with reference to the drawings, it being understoodthat various changes and 40 modifications in the particular apparatus and procedure to be described can be made without departing from the invention.

In the drawings:

Fig. 1 is adiagram showing schematically an electric circuit that may b employed-in prac ticing the invention; a

Fig. 2 is a perspective view of an electrode ele ment thatmay be employed; l

Fig. 3 isla side view of a standard form of rod or spindle employed in permanent waving Fig.4 is an elevation view showing a lock of, hair partially wound upon thespindleshownin, Fig. 3, with the electrode elementshown in Fig; 2

Stage when the hair became 3 Fig. 5 is aview taken approximately in the plane V-V of Fig. 4;

Fig. 6 is a view showing a lock of hair completely wound upon the curling rod and then in place ready for application of heat; and

Fig. '7 is a sectional view taken approximately in the plane VII-VII of Fig. 8.

Referring first to Fig. 1, there is illustrated schematically the essential elements of a practicable circuit that may be employed for controlling heating periods of an electrically energized permanent wave machine. Most of the elements shown in Fig. 1 may be conveniently housed in a cabinet which is represented schematically by the dotted line I.

The cabinet I contains a current indicating meter 2 having a hand or needle 3 adapted to move across a scale 4; a power transformer I; a rectifier tube 8; a filter condenser I; a resistor 8; a relay 9; a power transformer ID; a pair of signal lamps II and I2, respectively; a battery i 3; a variable resistance l4; and a switch II. The meter 2 is so mounted that. its face is visible and separate knobs are preferably provided on the exterior of the cabinet for actuating the switch I! and the variable resistor i4. Extending from the cabinet are a pair of wires "and I3, respectively, adapted to be connected to a suitable supply of alternating current, such asthe usual l10-volt lighting circuit. There also extends from the cabinet a pair of conductors l3 and 20, respectively, for energizing the permanent wave machine proper, which is not shown in Fig. ,1, and a pair of conductors 2| and 22 respectively, which extend to a pair of electrodes adapted to make contact with a portion of the hair that is being waved.

connection 35 to winding 21.

There will be described later a specific electrode structure that may be conveniently employed with existing hair waving equipment. For the present it may be assumed that the conductors 2| and 22 connect to electrodes 23 and 24, respectively,'which are in contact with a mass of the hair (schematically indicated at 23 in Fig. l) which is in the process of being waved.

When the conductors I1 and II are connected to a source of alternating current, and the switch I5 is closed, the primary winding 23 of transformer 25 is energized, thereby energizing the secondary windings 21, 23 and 29, respectively. Current from winding 23 heats the cathode 30 of the vacuum tube rectifier 3 and current from winding 21 flows alternately from opposite ends thereof through anodes 3| of the tube to the cathode 30 thereof, thereby applying potential to a conductor 32 which connects through resistor 8 to the winding of relay 3 to a contact 33 in the meter 2, and when the needle 3 is in the position shown in Fig. 1, a contact 34 thereon lies against the contact 33, completing a circuit through the needle to ground 34 and back through a ground Under the conditions described, a current will flow through the relay 9, energizing the latter, causing it to ataasasos ing machine, thereby supplying power to energize the machine. So long as power is applied to the permanent wave machine through conductors l3 and 20, the lamp II is energized by current supplied from conductors l9 and 20 through the transformer l0. Of course whenever relay 3 is energized to break contact between armature 33 and back contact 31, the current supplied to the permanent wave machine and to the lamp II is broken and the lamp II is extinguished. However, when the relay 9 is energized, the armature 33 closes on the front contact 33, thereby completing a circuit from one end of the secondary winding 29 through conductor 40, armature 36, front contact "and lamp l2 back to the other end of winding 29, thereby illuminating the lamp I 2. Lamps II and I 2 are preferably of different colors; thus lamp ll may be green and lamp I2 may be red. When the green lamp H is illuminated the operator is apprised of the fact that current is being applied to the permanent wave machine. When the green lamp is extinguished and the red lamp I2 is illuminated, the operator is thereby apprised that the control device has cut oil. the current supply to the permanent wave machine.

It will be observed that the relay 3 can be energized to cut oil the current supply .to the permanent wave machine over conductors I3 and 20 only when the contacts 33 and 34 within the meter 2 are closed. Closure of contacts 33 and 34 normally occurs only when the current flowing through the instrument 2 is zero or has a relatively small value.

As previously indicated, current for energizing the meter 2 is supplied from the battery l3 through the electrodes 23 and 24, which are in electrical contact with a mass of hair 23 which is being waved. Therefore all current applied from the battery l3 to themeter 2 must flow through the mass of hair 23 and the value of the current flowing at any instant will be determined to a large extent by the resistance of the hair 25,'since the resistance of the winding of the meter 2 is relatively low in comparison with the resistance of the hair.

For the reason that the hair of different individuals diflers substantially in resistance characteristics and-that it is impracticable to attempt to always position 'the same volume of hair at the same pressure and in the same configuration bertween the electrodes 23 and 24, the absolute value of .the resistance of the hair 25 in successive different operations will vary quite widely. However, in accordance with the present invention, I can compensate for such variations by varying the sensitivity of the meter 2. Such variations in sensitivity are effected by varying the variable or adjustable resistance i4 connected in shunt to the meter 2, so that only a portion of the total current passing through the hair is applied to the meter winding, and this portion may be varied according to the absolute resistance of the parrticular mass of hair being tested. Such variations in the sensitivity of the meter 2 are'permissible because I depend upon relative changes in the resistance of the hair and not upon the absolute value of the resistance. 7

A full explanation of the operation will now be given by describing the actual mode of procedure that may be employed.

Assume that the head of hair to'be given a permanent wave has been treated with the permanent waving solution; the hair wound upon the curling rods of the waving machine, which it is assumed will be electrically energized, and the 2,285,895 machine connectedto the conductors l3 and 20 (switchjl I! being open at this time). Assume further theta portion oitheh'ai-r on one of. the curling rods of the machine is positioned between the electrodes 23 and 24, and that the variable resistance ll is adjusted to its maximum value so that it does not] materially reduce the serial- 1 tivity otthe meter 2.. i n

The meter 2 is chosen of such sensitivity relative to the potentialot-the battery, and-the normal i'urtheri resistance or the mass of hair positioned between-the electrodes 23 and 24 that underthe conditions described, the needle .3 will 20 c the circuit previously traced from supply conmove a short distance, carrying the contact 34 the needle moves is not particularly pertinent.

away irom the contact 33. The exact distance Having completed the operations describedand having observed that the needle 3. has moved to operator closesl the switch ,l ipthereby completing ductors J1 and I! over the armatureand back contact or the relay ato the conductors I9 and l extending, to thepermanent wave machine. The

latter is, therefore energized and heat is applied to the curling elements on which i the hair. is

wound.

For purposes oi' the present invention, it is immaterial how the heatia generated within the curling elements. They may contain electrical heatingelementaeach electrically connected .to

hair between the electrodes? and. 24 decreases quite markedly, thereby causing the current through the meter .2 to be increased, and causing the needle 3to rise furthenuponthe scale.

The operator observes the rise of the needle .3,

particularly with reference to the maximum reading or the instrument. In this connectionit may be stated that. the resistance 01' the hair during the waving process first decreases to a minimum valueand then increases. When the resistance of the hair has reached itsminimum value, the

needle 3 will have moved a substantial distance over thescale l and thereaiterwill begin to retrace its movement. As soon as the operator notices that the needle hasbegun to move back toward thezero position, she adjusts the variable resistance 14 to reduce the sensitivityoi the instrument suflicientlytobring the needle back to oneoi'the three marks L, M or T on thescale foith'e instrument. It isunderstood of course that the instrument 2 is chosen of suchsensitivity that with the highest resistance hair obainable in practice the maximum reading of the instrument in its most sensitive adjustment will exceed the point T on the scale. m

Having ref-set the needle to one of the L, M or T, -the operator pays no more attention to the machine, since from that point on it is ter' to move, armature 36. chitsback contact 31 and thereby interrupt thesupplyof current from conductors l9 and 20 to the permanent wave machine, deenergizing the latter and stopping- ]carry the contact 3 clear of the contact", the

. scale division.) from theinstrument' or its circuit opened,it is theheating of the hair-curling elements. The

operator is apprised of the completion oi the operation by the extinguishing oi the green lamp I i and the illuminating of the red lamp 12. She thereupon opens switch I5, which deenergizes the apparatus within thecabinet.

1 Whichever one of the three indexes L M or T --theneedle 3 is re-set to, when the current has reached or passed its maximum value, is deter- .mined bythe type of wavedesired. Thus the index L signifies a loose wave, since it will require a relativelyishort time for the needle to drop from thisindex to the point of closure of con- -tact33and 34. Theindex M signifies amedium wave and if the needle is set to this point it will require a longer time for the needleto drop back to the position'oi contact closure andhence the heating time will be longer. The index T signifles a tight wave and if the needle is re-set to index T, then thetime required for the needle to dropback to the point or contact closure will be greatestand accordingly the heating time will be longest It is understood, of course,that the that as shown jinFig. 1 the position of the needle 3 at the point of closure oi. contacts 33 and 34 corresponds to a scale deflection or 5 on the scale 4. of the instrument and that the index T is located oppositefthescale indicator I5. (It is immaterial in the present discussion in what units the scale. is=calibrated provided theinstrument is fairly accurate so that each scale division indicates the' current flowing through the instrument when the needle is oppositethat Now it the shunt I 4 is removed obvious that the needle in moving from the scale division IE to the scale division 5 will represent a decrease in value of'66% in the current, since the current required to produce a deflection 01' 5 is one-third of that required to produce a deflection of l 5. This relation is not changed when the shunt I4 is employed to reduce the sensitivity of the meter provided the resistance It does not change its value during the operation. This means, of: course, thatthe resistance I4 must be of material having a low temperature coefllcient or of suflicient size that the current passing therethroughdoes not heat it appreciably. This selection of the three indexes L, M and T is pureresult is readily obtainable in practice. Stated in other words, at any given setting of the resistance H, the total current delivered by the battery l3 will always divide between the resistance l4 and the instrument winding in the same proportion. Thus if theresistance i4 is so adjusted as to beequal to the resistance of the instrument 2, then the current will divide equally between the shunt resistance and the instrument, irrespective of variations in magnitude inthe current and movement of the needle from the scale division l5 to the scale division 5 will always represent a decrease in value of the current of 66%% irrespective of the total value of current flowing. This means that ii, when the current has reached its maximum value the resistance I4 is varied to bring the needle 3 to the scale division I5, then, when the current flowing through the hair subsequently drops to one third, or mi /5% of its maximumyaluathe needle' 3 will have dropped to the point 5 on the scale, thereby closing the contacts 33 and 34.

It will be observed, therefore, that with the arrangement described, a drop of 66%% from the maximum value of the current flowing through the hair is accurately measured and indicated,

irrespective of the absolute value of the current at the time of maximum flow.

I have found in practice that if the point -T is located at a scale setting three times the scale setting corresponding to closure of contacts 33 and 34, thereby interrupting the heating circuit when the conductivity of the hair has dropped to one-third of .its maximum value, that a good, tight curl or wave will always be obtained.

In order to obtain what is termed in the art a medium curl, I find it necessary to interrupt the heating when the conductivity of the hair has dropped to substantially half of its maximum value. Therefore the index M is positioned at the scale division l when the point of contact closure is at the scale division 5.

In order to obtain what is termed in the art a loose curl, I find it necessary to interrupt heating of the hair when the conductivity of the hair has dropped only slightly, to about five-sevenths of its maximum value. Therefore the index L of the meter 2 is positioned opposite the scale reading 1.

As previously pointed out, the actual structure for applying heat to the hair while it is being curled is not shown at all in the schematic diagram of Fig. l, and the elements for effecting electrical contact with the hair are shown schematically as plates 23 and 24. An actual waving rod that may be employed in connection with my invention, will now be described with particular reference to Figs. 2, 3, 4, 5, 6 and 7.

Referring first to-Fig. 3, there is illustrated a well-known form of curling rod or spindle employed for permanent waving. It comprises a tapered spindle 50 having a roughened surface for increasing friction with the hair to facilitate winding of hair thereon and'having large end portions 52 for the reception of bands 53 and 54 which support a clamp 55 for securing the wound hair against unwinding during the heating operation. The collar 53 may be mounted between a pair of flanges'on the end of the spindle, as shown, so that it remains in position at all times. The collar 54 on the other hand is free to slip over the end 56 of the spindle and to facilitate compressing the clamp 55 against the hair, a tensioning lever 51 is usually provided. The clamp v55 may be constructed of rubber or other yieldable material. The spindle or rod 50 is preferably of hollow metal construction and encloses an electrical heating element, the two ends of which are connected to prongs 58 and 59 which project into recesses in the two opposite ends of the spindle. Electrical connections from a common source of supply to the heating element is had by means of socket members 60 which are pressed into therecesses in opposite ends of the spindle and make electrical connections with prongs 58 and 59, respectively. The sockets are connected by suitable insulated wires to the source of supply which may be constituted by extensions of the conductors I9 and 20 in Fig. l. A small metal clamp 62 is hingedly mounted on the spindle to aid in looking the ends of a lock of hair to be wound upon the spindle.

In practice, the collar 54 is released from the end of the spindle and the connecting sockets 60 removed from the spindle. The clamp 62 is then swung away from the spindle and the ends of a lock' of hair placed against the spindle and secured in place by pressing the clamp 62 down thereover. The lock of hair is then wound onto the spindle by rotation of the spindle, such rotation being facilitated by a knurled end portion 63 which can be twirled between the fingers.

In accordance with prior practice, the hair is wound in as nearly uniform layers as possible on the spindle until the latter is close against the scalp and then the clamp 55 is locked into position with the clamp against the scalp to support the spindle and the hair thereon a slight distance away from the scalp so that the scalp will not be burned when the spindle is heated. The sockets 60 are then plugged into the rod and the heating current applied.

The mode of winding the hair onto the spindle is exactly the same when employing my invention, except that an auxiliary electrode for measuring the resistance of the hair is wound up with the hair on the spindle. Obviously, an electrode, in order to be wound up with the hair on the spindle, must be flexible. Such an electrode is disclosed in Fig. 2 and comprises an elongated strip 65 of thin metal foil to which there is secured a coating 66 of insulating materialwiuch may be Cellophane. A Cellophane strip may also be extended along one side only of the foil strip 65 beyond the area of complete enclosure by the Cellophane. Thus such a backing strip is indicated at 61 in Fig. 2. It is not essential, however. The strip 65 has an exposed conductive surface 68 of fixed area. The Cellophane enclosure 66 is convenient in handling the strip. One end 69 of the foil projects a short distance beyond the Cellophane covering 66 to facilitate the making of electrical connection to the foil. The electrode structure disclosed in Fig. 2 is introduced between successive layers of hair on the spindle when the spindle is spaced a few inches away from the scalp, as clearly shown in Figs. 4 and 5, the foil being wound up on the spindle between the successive layers of the hair with the surface 68 of the foil toward the spindle. The'length of the exposed portion of the foil face 68 is such as to extend substantially one turn about the spindle with an average amount of hair thereon. When the hair is all wound on the spindle, as shown in Figs. 6 and 7, a small portion of the Cellophane 66 and the exposed end 69 of the foil project away from the coiled hair and electrical connection is made to the foil by snapping a spring clip over it, as shown in Figs. 6 and 7. The foil strip constitutes one of the electrodes 23 or 24 in the schematic diagram of Fig. 1, and the other electrode is constituted by the metal spindle itself on which the hair is wound. Hence connection to the other electrode is effected by snapping a clip leading from one of the conductors 2| and 22 over any exposed metal part of the spindle. It is to be understood that the electrical heating element within the spindle is electrically insulated from the spindle so that there is no circuit connection directly between the heating element and the spindle body.

It is the usual practice to also wind up with the hair during substantially the last revolution of the spindle, a sheet of Cellophane or other sheet material relatively impervious to moisture, to act as an insulating medium to enclose the hair and insure uniform heating and steaming thereof, when the spindle is electrically heated.

It will be obvious from an inspection of Figs.

4, 5, 6 and 7 that it is impossible, in practice, to

always position the same amount of hair at the same pressurebetween the two electrodes corresponding to electrodes 23 and '24 in Fig. 1 (one of these electrodes being the spindle and the other the foil strip 65, in practice). Therefore, even if all hairhad the same resistance characteris-,

tics it would be impossible to always obtain the same absolute values of current flow between the two electrodes.

the absolute magnitude of the current are-not strument to function in a definite predetermined important, however, in view of the use of the shunt resistance element 14 on the instrument 2 which functions asanadaptor to adapt the in manner in response to percentage changes in the current through the hair,irrespective or the absolute magnitude of the current. i

Oi coursein practice a'iarge number of the curling spindles orrods described areemployed in order to wave all the hair on a head. It is not necessary, however, to test the resistance 01' the hair upon all of the rods. With a normalhead or hair, it is suillcient to incorporatethe electrode structure described in only one of the rods and control the application of heat to all of the rods in response to the changes in resistance of the hair on the one rod. In some instances, as the] result of scalp injuries, the hair on dlfl'erent portions of a single scalp has such diil'erent physlcal characteristics that different heating times are required. In such cases, of course, the hair on each different portion or the scalp is waved separately from the rest and the time or each operation controlled by changes in the resistance ance of the particular hair being waved, success- T iul results are automatically obtained without the exercise of skill on the part or the operator. Although the invention has been explained by describing in some detail a particularapparatus that may be employed, it is to be understood that radical changes can be made from the particular I claim: l L'The method or determining the progress oi. a permanent hair waving operation, whichcomprises ascertaining and indicating variations in the electrical resistance of a portion at least of the hair'during the operation. L

55 2. The method 0! gauging the length or the heating period in thepermanent waving othair, which comprises continuously ascertaining changes in electricalconductivity of a portion Such unavoidable variations in or said hair during the heating period, and ter- 'minating the heat when the conductivity falls to apredetermined fractionof its maximum value.

3. In combination, means for supporting and heating treated hair to impart a permanent wave thereto, and means for simultaneously ascertaining and indicating variations in the electrical conductivityoi a portion at least of said hair being heated, whereby changes produced in the hair by the heating operation may be ascertained.

4. In combination, means for supporting and heating treated hair to impart a permanent wave thereto, means for simultaneously ascertaining variations in the electrical conductivity of a portion at least 0! said hair being heated, andmeans responsive to a, predetermined change in said conductivity for controlling said heating means.

5. In combination, means for supporting and heating treated hair to impart a permanentwave thereto, means for simultaneously ascertaining variations in the electrical conductivity of a portion at least of said hair being treated, said lastmentioned means, comprising electrode meansior contacting a mass or hair while the latter is being waved, a; source of current and a currentresponsive device connectedwith said electrode means. a

8. Apparatus as described in claim 5, with means for varying the degree or response of said current-responsive device to current flowing through said hair. n a i r 7. Apparatus as described in claim' 5, with means for varying the sensitivity of said ourrent-responsive device. a

8. Apparatus as described in claim 5, and an adjustable current conducting element con- 1. nected in shunt with said current-responsive device for varying its degree of response.

9. Apparatus asdescribedin claim 5, in which said hair supporting-and heating means includes a-spindle on whlchhair is wound, said spindle constituting a part of said electrode means, and a flexible conductive-sheet element adapted to be wound with hair upon such spindle and constituting another element oi! said electrode means.

10. In a permanent waving apparatus, means "-for heating hair, means cooperating with said heating means for testing the electrical conductivity of the hair while being heated, and means responsive to said testing. means for controlling said heating means. 1

11. In a permanent waving apparatus, hairheating means, and means for controlling said heating means in response to variations of electrical conductivity of hair heated by said heating means. e I

JAMES ALBERT MAIZE. 

